Hybrid electric vehicles (HEV's), plug-in hybrid electric vehicles (PHEV's), battery electric vehicles (BEV's), fuel cell vehicles and other known electrified vehicles differ from conventional motor vehicles in that they are powered by one or more electric machines (i.e., electric motors and/or generators) instead of or in addition to an internal combustion engine. High voltage current is typically supplied to the electric machines by one or more batteries that store electrical power.
Electrified vehicle batteries may employ one or more battery cells, such as lithium-ion battery cells. Tests for evaluating the safety of such battery cells are known. One common evaluation test is referred to as the nail penetration test. During this test, a nail is driven through a battery cell to create a short circuit inside the battery cell. In response to the destructive test, battery temperatures and voltages are measured. One drawback to known battery penetration tests is that these tests reveal little to no detail concerning the internal response of the battery cell.